Hot water heating system



m 1 D. E. MORGAN HOT WATER HEATING SYSTEM 4 Sheets-Sheet 1 Filed May 12,1955 EM IOQ INVENTOR. DAVID E. MORGAN BY QQuxA,Qzo.9 QMQM OWL (0c mommaATTORNEYS June 19, 1956 MORGAN 2,751,156

HOT WATER HEATING SYSTEM Filed May 12, 1955 4 Sheets-$heet 2 AIR ELIM-INATION CHAMBER AUTOMATIC AIR VENT Fig. la

Fig. 1d

INV

DAVID E. MORGAN ATTORNEYS n 1956 D. E. MORGAN HOT WATER HEATING SYSTEM 4Sheets-Sheet 3 Filed May 12, 1955 25 1 nPEfiw mo. 5um o N025 mi; N. 9 ao v N c on I. 3 on M 3 w 02 m H 3 cm. m. s n o! a zoFzm z 1:; Mai 122. mM ow.

w. 3 U 2: B J a COM ofl'l] 1i.

INVENTOR. DAVID E. MORGAN ATTORNEYS n 1 D. E. MORGAN HOT WATER HEATINGSYSTEM 4 Sheets-Sheet 4 Filed May 12, 1955 o o o m m mm W TM m m W W D 5m, M 0 F ATTORNEYS HOT WATER HEATING SYSTEM David E. Morgan, Westmont,N. J., assignor to Warren Webster & Company, Camden, N. J., acorporation of New Jersey Application May 12, 1955, Serial No. 507,852 9Claims. (Ci. 237-8) August 2, 1954, now forfeited, and entitled HotWater Heating System.

Although such circulating hot water systems have long to circulate hotwater through the relatively cold radiating system, the resulting rapidexpansion of the piping, radiators and the radiating fins causesannoying snapping, pings and chunk noises. Similar troublesome noisesalso occur to some extent on each occasion when the the coldest weather.With such widely spaced intervals of heating of the circulating water,its maximum temperature during the on intervals may exceed, for example,200 P. so that when the thermostat acts'to stop the circulating pump,there will be so much excess heat available in the radiators and thewater therein, that the ensuing off period will be prolonged, and whilethe actual room temperature may remain resonably close to the d siredvalue during the off intervals, yet the radiators will have time tobecome so cool that they will not give off radiant energy but will inefiect absorb radiant energy from the atmosphere in the room and fromthe occupants so that a condition will exist which is sometimes referredto by heating experts as a cold 70 temperature. In short, although thetemperature of the room atmosphere may remain reasonably close to thedesired level, yet the a range, for example, of more than 125 F whichgives rise to a feeling by the occupants of pronounced alternate coolingand heating.

Attempts to secure more uniform heating have included use of well-knownforms of so-called anticipating thermostat arrangements such that thethermostat will be actuated to start an off period somewhat prior to theintervals somewhat prior to the lowering of the room temperature to itsminimum level. But while such anticipating thermostats tend to regulatethe room temperature more closely to a predetermined value, they have nosubstantial effect upon reducing the widevariaof the temperature in thecirculating water itself, and

returned from the radiating system and is mixed with the hot water byway of such by-pass. With such a bypass, each time when the circulatingpump is started there will be a slight delay before the watercirculating in the lower than the boiler water temperature, theseresults being due to the fact that the circulated water comprises amixture of hot boiler water and relatively cool returned water comingthrough the by-pass. Thus while such a bypass, to some extent,diminishes the problem of niomentarily excessively hot radiators duringmild weather, it tends to prevent flow of a suthciently hot stream to insure most eflicient cold weather heating. And while the use of theconventional by-pa'ss causes a slight delay in bringing the circulatingWater up to the desired temperaperature during on and off periods willstill vary within such a wide range as to give occupants alternatesensations of overheating and excessive cooling and the diflicul'ty willremain even though the above-described anticipating types of thermostatarrangements are used.

The present invention involves a means and method for avoiding orsubstantially minimizing the above-noted difiiculties in arelatively'simple', reliable and inexpensive Way, whereby the variationsin the circulating water temperature during the on and off periods maybe kept within a quite narrow range, thereby avoiding the troublesomenoise effects and at the same time giving the room occupants a feelingof quite uniform heating;

According to the present invention, a by-pass as above described isused, preferably one which has a predetermined and relatively small orsomewhat restricted passage. At the point where the by-passe'd watermixes with the outcoming hot boiler water, aheat-responsive valveoperating device is inserted, this device being connected to operate avalve which controls the flow of the outcoming hot boiler water. (Insome cases, but not preferably, this valve alternatively mightbelocatedat the juncture of the by-pass and the returnline to theboiler.) The valve element has a small aperture or apertures, or anequivalent by-pass, through whichat least asmall quantity of the hotboiler water may flow whenever the pump is operating and even thoughthe" valve may otherwise be closed so far as normally p ssible'. Thuswhen the circulating pump is initially started, it will cause a smalltemperature suitable for mild weather heatin and it the weather is mildthe circulating pump will be stopped by its thermostat before theradiating system is excessively heated. Furthermore, the radiatingsystem during this period will only gradually become heated and thetroublesome noises will be avoided or eliminated. However, if theweather is cold enough to require operation of the pump for a longerinterval, then after such period of five or ten minutes, the circulatedwater in the radiating system will have reached a temperature such as tooperate the above-mentioned heat-responsive valve means thereby openingthe valve which it controls, to the extent necessary for allowing alarger stream of hot water to come from the boiler and mix with thereturned by-pass water thereby bringing the radiating system up to thenecessary higher temperature for cold weather heating, But since theheating of the radiating system has been gradual, there will still be nosudden application of hot water to relatively cool metal parts and as aconsequence the troublesome noises will be largely avoided oreliminated.

Usually to secure the most satisfactory results from the above-describedspecial heat-responsive valve and by-pass, one should use theabove-described anticipating type of thermostat arrangement or theequivalent. While without such special valve and by-pass theanticipating thermostat arrangements have no substantial elfect towardminimizing the fluctuations in the circulating water temperature, yetwith such special valve and by-pass means, the anticipating thermostatmeans will permit the water temperature to be confined to anexceptionally narrow range, for example, from about 8- in a typical casein cold weather up to about 10-20", for example, in warmer weather, theposition of such range on the temperature scale shifting automaticallyaccording to the heating requirements and the range being high enough toinsure that some heat will always be given off by convection as well asradiation.

Preferably, a valve is inserted in the boiler water outlet connection inadvance of the connection to the bypass, which valve is of aconstruction adapted to open only when the circulating pump causes aflow under pressure to occur therethrough, this valve at other timesremaining closed to prevent gravity circulation of water through thesystem at times when the thermostat does not call for operation of thecirculating pump.

Other and more specific objects, features, and advantages of theinvention will appear from the detailed description given below, takenin connection with the accompanying drawings and forming a part of thisspecification and illustrating by way of example the presently preferredembodiments of the invention.

In the drawings:

Fig. 1 is a diagram schematically showing a boiler and associatedheating system including the combinations of features involving thepresent invention;

Figs. la-le, inclusive, are schematic diagrams showing various possiblealternative arrangements for the connection of the various units of thesystem;

Fig. 2 is a vertical sectional view through the special device orheat-responsive valve means located at the junction of the hot wateroutlet conduit coming from the boiler and the by-pass connection;

Fig. 3 is a sectional view taken substantially along line 3-3 of Fig. 2;

Fig. 3a is a side view on a smaller scale of a valve assembly like thatof Fig. 2, except having a by-pass permitting a limited flow, past thevalve in lieu of utilizing valve apertures as of Fig. 3 for thatpurpose;

Fig. 4 shows certain time-temperature curves indicating the temperatureconditions of the circulating water with and without the presentinvention; and

Fig. 5 shows portions of a circular type temperature recorder dial orgraph and indicating an actual example of the circulating watertemperature range secured by the use of the invention over a periodstarting at 6 o'clock on one evening and ending thirty-six hours later,the con current room temperatures and outdoor temperatures for thisperiod also being indicated.

Referring to Fig. l in further detail, a boiler is indicated at 10provided with any well-known form of fuel burner as indicated at 11which operates under the control of a boiler thermostat schematicallyindicated at 12 whereby generally the boiler water will be maintained ata suitable substantially constant predetermined temperature. The hotwater outlet conduit from the boiler is indicated at 13, and to which aconventional expansion tank is connected as indicated at 130. Ifdesired, the expansion tank construction and arrangements may be used asdisclosed in the co-pending application of David E. Morgan and James E.Tolan, Serial No. 378,512, filed September 4, 1.953. Conduit 13 includesa valve 14 of a suitable known type having a valve-piece which willnormally be closed as by gravity to prevent any gravity flow of waterthrough the system when the circulating pump is not operating. From thevalve 14 the hot water next flows into a device or valve 15, such asshown in further detail in Fig. 2. From the device 15 connections areprovided, such as shown at 16, 17, 18, etc., for conducting the hotwater to the various radiators, as indicated at 17 13', 19, etc., eachradiator being provided with a return connection communicating withreturn lines as at 20, 21, 22, running to an air elimination device at22 of any suitable known type, thence to an electric motor-driven pump23. This pump discharges the return water through a conduit 24,partially into a by-pass connection 25 and partially into a returnconnection 26 into the boiler.

The pump is controlled in a known way by a room thermostat 27 connectedby means of a relay 27'- to control the circuit of the pump motor so asto start such motor whenever the room temperature decreases to apredetermined point and to stop the motor when the room temperaturerises again to a predetermined degree. As above indicated, thisthermostat arrangement is preferably of the type which is hereinreferred to as an anticipating thermostat. That is, in series with thecontacts of the thermostat 27 and with the coil 28 of relay 27', anadjustable heating resistance 29 is connected. Assuming that thethermostat contacts are in closed position during an on interval ofoperation of the circulating pump, then the resistance 29 will causesufiicient heating of the bimetallic strip of the thermostat 27 to causethe contacts to open shortly before the maximum desired room temperatureis reached, that is, in anticipation of such maximum temperature. Also,the thermostat contacts are so adjusted that during an oil interval ofoperation of the circulating pump, such contacts will remain open onlyuntil the room temperature decreases to a value slightly above theintended minimum room temperature, thus causing the next on interval tostart in anticipation of the minimum room temperature. Generally theresistance 2 is so made or adjusted as to have about the same value asthe resistance of the remainder of the circuit, viz., largely that ofthe relay coil 28. But with the present invention, preferably althoughnot necessarily. the resistance 29 is made adjustable whereby, as willbe hereinafter made apparent, the range of fluctuations of thecirculating water temperature may be varied. That is, simply by movingthe adjustable contact on resistance 29 to include in the circuit lessresistance, one may with the system of this invention limit and decreasethe circulating water temperature rangefor by moving such contact 50 asto include in the circuit more resistance, one may secure a wider watertemperature range.

The radiators may be of any suitable known type, for example, some maybe of the conventional cast iron type such as at 17', 1?, or some or allmay be of the finnedtube type as at 18.

The by-pass connection 25 preferably comprises a pre- -rate of flow willbe forced out determined length of tubing, for example, ten feet ofrelatively flexible copper tubingof a diameter generally boiler, suchby-passes may beformed. of tubes of the above-stated length and anyavailableexcess of the tubing in particular installations maybe coiledas at 250.

Referring now to Fig. 2, the/device a T-shaped coupling, connected atboiler the otherside to the outgoing pipe of the circulating system; thethird branch of the T being directed downward and connected to theby-pass 25. Within the mid-portion of. the body of this coupling thereis located a heat-responsive valve actuator 39 of some suitable knowntype, for example, a construction operating according to the to-Vernet,No. 2,115,501, Howthat various other known types of heat-responsivevalve operating devices may be used for the purpose, same beingconnected to the actuated valve element, such as a butterfly type ofvalvepiece 31, which normally when closed is positioned in a verticalplane and has apertures 32 therethrough tov allow some hot water fromthe boiler to pass even when the valve otherwise is closed.Alternatively, instead of forming the valve-piece itself with aperturesit will be appreciated that an equivalent might be provided by soconstructing or adjusting the valve-piece or its actuator that the valvewill never entirely close but will allow a small stream to by-pa'ss thevalve-piece even when thrust as far as it will move toward closedposition. Or, alternatively, a small by-passas at 32' may comprise oneside to the hot for controlling or varying the flow through the bypassThe heat-responsive element and the piece may be formed as a unitaryassembly and msertable into the body of the device shown and thenremovably clamped in place as by the use of a nipple 33 and a threadedring or annular clamping nut 34. A gasket 35 is provided between nipple33 and the peripheral flange 36 on" the valve assembly. Preferably, inorder to insure that the valve apertures 32 will be located at apredetermined position at the upper-side remote from the by-pass 25, theassembly flange 36 is provided with a pin, or the like, 37 for. engagingin a corresponding hole formed in the body of the device 15.

The operation of the system according to the invention will now bebriefly reviewed. Assuming that theroom temperature falls to a degreesuch as to soon require heat, then the thermostat 27 will act throughrelay 27 to close the pump motor circuit and water will. be pumped fromthe radiator system through the aireliminator 22', thence through thepump 23,. thence partly through the by-pass 25 and partly through thereturn pipe 26 into the boiler. Then hot water at a limited of theboiler through connection 13, valve 14 and through the valve apertures32 (or the equivalent) into the mid-portion of the device 15. At thispoint, this limited amount of hot boiler water will mix with the coolwater returned through the by-pass 25 and the resulting mixture ofintermediate temperature will be forced out through the radiating systemand back to the pump. But after, for example, five or ten minutes themixture as circulated through the radiating system will have increasedin temperature enough, so that when mixed with additional hot boilerwater coming through apertures 32, it will cause actuation of theheat-responsive means 36 and opening or" the valve 31. However, ifbefore this happens, the room temperature has risen enough to actuatethe ther-- 6 mostat 2-7,. the: pump will..- be stopped with consequentstoppage; of: circulation of hot: water through the radiating system. Atthe: same time valve 14 will automatically close. to prevent furtherflow of hot water to or from the boiler. by the action of gravity. theradiating system and'its conduits will the required length of theheating cycle during cool or colder weather. Finally, when the room.temperature reaches a level causing the thermostat temperatures of thedegree. required during cool or colder weather.

Fig. 5 shows'the results. of an actual test of the system over a typicalperiod of thirty-six'hours during which the room temperature wasretainedsubstantially constant, that in the pipe running to the radiators) waskept within a R, the: median value gradually increasing by amountscorresponding to the gradual decrease of the. outdoor'temperature andthe range graduallydecreasingswith.colderweather. Thus, although thevals, the water temperature varies above and below a At the same timethere is no excessive eating. of the radiators when the weather is mildor excessive cooling of the radiators even for momentary intervals whentheweather is cold.

The advantages of the invention may be appreciated fromthe following:facts. If the water temperature curve of Fig. 5 were for a conventionalcirculating hot water heating system of the on and oif type with noboiler bypass, then such curve. would zigzag between points in theneighborhood of 200 F. down to room temperature or possibly less. And ifthe system were one with a welldesigned boiler by-pass but without thethermostatically controlled valve as at 15 herein disclosed, then thiswater temperature curve would ordinarily zigzag over an intermediatewide range, say of 100 F. or more, and the result would be the samewhether or not an anticipating type of thermostat arrangement were used.The troublesome noisy conditions would occur as would also the cold 70degree sensations during off intervals. With the bypass 25 accompaniedby the special thermostatic valve 15, but without an anticipating typethermostat, the zigzag range of the water temperature would beconsiderably more limited than with either of the other twoabovementioned conditions. But with the anticipating thermostat added,the upper and lower temperatures of the circulating water may be notonly brought substantially closer together, but the degree of closenessthereof may be very easily adjusted by simply adjusting the contact onresistance 29. While it is desirable to keep the water temperature rangewithin as narrow limits as possible, yet if the range is made toonarrow, then the frequency of starting and stopping of the circulatingpump may become excessive or annoying, particularly when the outdoortemperature is colder. With the example of the water temperature curveshown in Fig. 5, there are about six on" periods per hour at the time ofthe start of the test, whereas during the colder and later periods ofthe test, the number of such periods per hour increased considerably andwith a consequent narrowing of the range of water emperatures. The moreabrupt changes in the water temperature range indicated in Fig. occurredas a result of opening doors or windows, yet it will be noted that theroom temperature remained substantially constant.

In Fig. 4, the full line curve shows the. results of an actual test andindicates the rate at which the circulating water temperature rises,upon starting the pump, to a maximum with delayed action over a periodof about nine minutes, when the boiler water temperature is at thepredetermined regulated temperature of about 210 degrees or slightlyless. The dash line curve in Fig. 4 on the other hand shows thetemperature changes which will occur without the combination of theinvention, that its, in a system the same as of Fig. l but without thetemperature responsive valve means in the device 15. Here it will benoted that immediately upon starting the circulating pump, the hotboiler water will be forced into the outgoing conduits of the radiatingsystem, thus filling at least portions thereof with water atsubstantially the maximum temperature almost immediately and causingthermal shocks and consequent noises throughout the radiating system.Then when relatively cold recirculated water has replaced the hot waterin the boiler, and also through the by-pass, has become mixed with theout-going boiler water, the temperature of the outgoing circulated waterwill drop sharply again approximately as indicated by the dash linecurve. causing further thermal shock and noises before the boiler waterand the circulated water gradually increase again in temperature. Theseconditions, approximately as shown by the dash line curve of Fig. 4,will thus cause two noisy intervals for each cycle of operation of thepump, when the present invention is not used. It should be further notedthat preferably the dimensions of the bypass 25 should be so related tothe size of the apertures 32 in the valve 31 that the resistance to howthrough these passages will have a predetermined relationship. Forexample, with a preferred embodiment of the invention, the threeapertures 32 were made circular with diameters of about 5/ whereas theby-pass 25 as above-mentioned was made of a length of tubing feet longand having an internal diameter of about 0.545" /6" 0. D. coppertubing). With these relative dimensions and with the boiler outlet pipe13 made of l" or 1% piping (standard iron pipe sizes), it was found thatwhen the valve 31 was closed. about 40% of the fiow to the heatingsystem would pass through the valve apertures 37. and the remaining 60%through the by-pass. These relative percentages of flow may, of course,be varied considerably, as may also the pipe and aperture dimensionsabove given, while still achieving substantially the above-describedadvantages.

It should be further noted that preferably all portions of the pipe 13between the boiler and the valve 15 should, as indicated in Fig. 1, bedirected upwardly from the boiler or inclined at least somewhat upwardlytoward the valve 15. This will insure that any bubbles of air which maybe contained in this pipe will pass on through the valve apertures 32which are located on the upper side of valve-piece 31. Thus theentrapment of air at any point in advance of the valve 15 will beavoided.

The system of the invention has an additional advantage useful in someinstances and which has not been mentioned above. With many householdheating systems, provision is made for obtaining domestic hot water bythe use of a water heater at the boiler. With such systems, it issometimes the practice to provide a reverse acting" control for thecirculating pump so as to prevent actuation of the pump and the heatingof the house when the boiler water temperature falls below a certainpoint, for instance 160 F. This allows the burner to raise the boilertemperature again quickly and to assure that the necessary supply ofdomestic hot water can properly be heated for a time by the boiler.During this time, of course, the house will not be heated because thecirculating pump is not in operation. However, with the presentinvention, such a reverse acting control on the circulating pump willnot ordinarily be necessary because when the boiler water temperaturetends to be rather low, the heat-responsive valve-actuating device 30will not operate to open the valve 31. Accordingly, the house heatingsystem may be kept in operation to at least provide some degree of heatwithout allowing enough hot water to be taken from the boiler to preventthe latter from heating the domestic hot water supply at times whennecessary, and then to permit the boiler temperature to rise to normal.

In difierent installations, the heat-responsive devices 30 may beselected or adjusted so as to start opening valves 31 at differentpredetermined temperatures depending upon the normal predeterminedregulated temperature level in the boiler. Usually, the device 30 may beadjusted or selected to actuate at or F., corresponding respectively tothe three common ranges of boiler water temperatures customarily used.

Although the locations of the various units of the system are preferablyas per Fig. 1, satisfactory operation or at least improved results maybe secured with the various other arrangements as shown in Figs. 1a tola, inclusive, wherein corresponding parts are identified by the samereference numerals as in Fig. 1. For example, in Fig. la the circulatingpump 23 is indicated as being located either in the boiler water outletor as at 23a in the outcoming conduit running to the radiators. That is,either one of the pumps as at 23 or 23a may be used while the other oneis inactive with the Water passing therethrough without being pumped, oreither one of these pumps may be omitted. In Fig. lb the specialthermostatic valve 15 is located at the juncture of the pipe returningfrom the radiators with the lower end of the bypass 25, the circulatingpump being located as in Fig. in. Fig. lc is the same as Fig. 1b exceptthat the circulating pump is located as in Fig. 1. Fig. 1d shows asystem like that of Fig. l, but with separate outgoing and returnconnections for five different heating zones, as may be necessary ordesirable, for example, in a large building. Fig. 1e shows anotherarrangement with separate devices and circulating pipes in outgoingconduits for five heating zones from which a single return connection 24is provided.

Although certain preferred embodiments of the invention are hereindisclosed for purposes of explanation, various modifications thereof,after study of this specification, will be apparent to those skilled inthe art to which s ght, the

the invention pertains. Reference should accordingly be had to theappended claims in determining the scope of the invention.

What is claimed and desired to be secured by Letters Patent is:

1. In a circulating hot water heating system, the com a radiating systemand including a return connection back into the boiler, said conduitmeans including therein a motor-driven circulating pump, thermostaticmeans for starting and stopping said motor-driven pump responsive totemperature changes, a relatively restricted boiler bypass having one ofits ends connected into said return connection and having its other endconnected into a device through which the outgoing hot boiler waterpasses to the radiating system, said device having therein aheat-responsive valve-actuating means located in a position to beresponsive to a predetermined temperature of the boiler into said devicebut being arranged with a restricted passage means permitting at least alimited flow of hot boiler Water to normally pass when the pump isoperating, for admixture with the returning by-passed water, and wherebyafter a period of delay following the starting of the pump, theresulting mixture will rise to said predetermined temperature and causesaid heat-responsive device to open said valve to allow a greaterproportion of hot boiler water to be circulated through the heatingsystem during the remainder of the interval of operation of the pump,such delay aifording time for the radiating system to be graduallyheated by a relatively low temperature water mixture before the valve isopened widely for providing higher temperature heating, rapid thermalexpansion and consequent noises in the heating system being therebysubstantially reduced.

2. In a circulating hot water heating system, the combination comprisinga boiler, conduit means for conducting hot water from the boiler througha radiating system and including a return connection back into theboiler, said conduit means including therein a motor-driven circulatingpump, thermostatic means for starting and stopping said motor-drivenpump responsive to temperature changes, a boiler by-pass having one ofits ends connected into said return connection and having its other endconnected into a device through which the outgoing hot boiler waterpasses to the radiating system, said device having therein aheat-responsive valve-actuating means located in a position to beresponsive to a predetermined temperature of the mixture of hot watercoming from the boiler and cooler return water from the by-pass, and avalve operatively connected to said actuating means, said valve beingpositioned normally to check the flow of hot water from the boiler intosaid device but being arranged with a restricted passage meanspermitting at least a limited flow of hot boiler water to normally passwhen the pump is operating, for admixture with the returning by-passedwater, whereby after a period of delay following the starting of thepump, the resulting mixture will rise to said predetermined temperatureand cause said heat-responsive device to open said valve to allow agreater proportion of hot boiler water to be circulated through theheating system during the remainder of the interval of operation of thepump, such delay affording time for the radiating system to be graduallyheated before said valve is Widely opened.

3. In a circulating hot water heating system, the combination comprisinga boiler, conduit means for conducting hot water from the boiler througha radiating system and including a return connection back into theboiler, said conduit means including therein a motor-driven circulatingpump, thermostatic means for controlling said motor-driven pump atintervals responsive to temperature changes in a space to be heated, aboiler by-p'ass having its ends connected respectively into the outgoingand return cohnecti'ons'of the system, one of said ends being waterpasses, said device having therein a heat-responsive valve-actuatingmeans located in a position to be responsive to a predeterminedtemperature of the mixture of circulated water and by-passwater, and avalve operatively connected to said actuating means, said valve beingpositioned normally to check the flow of circulating boiler water butbeing arranged with arestricted passage means permitting at least alimited flow of circulating water normally to pass whenever the pump isoperating, whereby after a period of delay following the starting of thepump the said mixture will rise to said predetermined temperature andcause said heat-responsive device to open said valve to allow a greaterproportion of hot water to be circulated through the heating systemwhile the pump remains in operation.

4. Apparatus accordingto claim 1 and in which an additional valve islocated in the hot water outlet conduit from the boiler, whichadditional valve is constructed and arranged to be normally closed whenthe pump is not operating, topreve'nt circulation of water through thesystem by the action of gravity, but to be automatically opened by theflow of water when the pump is operating.

5. In a circulating hot water heating system, the combination comprisinga boiler, conduit means for conducting hot water from the boiler througha radiating system and including a return connection back into theboiler, said conduit means including therein a motor-driven circulatingpump, an anticipating thermostatic arrangement for controlling saidmotor-driven pump to start and stop the same at intervals responsive totemperature changes in the spaces to be heated, a boiler by-pass havingits ends connected respectively into the outgoing and return connectionsof the system, one of said ends being connected into a device throughwhich the circulating water passes, said device having therein aheat-responsive valve-actuating means located in a position to beresponsive to a predetermined temperature of the mixture of circulatedWater and by-pass water, and a valve operatively conand cause saidheat-responsive device to open said valve to allow a greater proportionof hot Water to be circuthrough which the circulating water passes, saiddevice having therein a heat-responsive valve-actuating means located ina position to be responsive to a predetermined temperature of themixture of circulated water and bypass water, and a valve operativelyconnected to said actuating means, said valve being positioned normallyto check the flow of circulating, boiler Water but being arranged with arestricted passage means permitting at least a limited flow ofcirculating water normally to pass whenever the pump is operating,whereby after a period of delay following the starting of the pump thesaid mixture will rise to said predetermined temperature and cause saidheat-responsive device to open said valve to allow a greater proportionof hot Water to be circulated through the heating system while the pumpremains in operation.

7. A circulating hot water heating system embodying the combinationspecified in the foregoing claim 5 and in which the anticipatingthermostatic arrangement includes an electrical heating element forapplying heat to cause actuation of the thermostatic means andconsequent stopping of the pump in anticipation of the desired maximumtemperature in the space being heated, said heating element beingadjustable to thereby permit adjustment of the range within which thetemperature of the circulating water varies during the intervals ofstarting and stopping of the pump.

8. A circulating hot water heating system embodying the combinationspecified in the foregoing claim 5 and in which the thermostaticarrangement includes a thermostatic contact actuating element, anelectrical heating element adjacent said operating element, a relay forcontrolling the pump motor circuit, said relay having a winding inseries with said heating element and the thermostat contacts.

9. A device for controlling the flow of water in a circulating hot waterheating system having a boiler by-pass, said device comprising a valvechamber with a main inlet and a main outlet for the circulating waterand also means for connecting into same one end of the boiler by-pass, aheat-responsive valve actuating means in said chamber and located in aposition to be responsive to a predetermined temperature of the mixtureof circulated water and by-pass water, and a valve in the chamberoperatively connected to said actuating means, said valve beingpositioned normally to check the flow of boiler water but being arrangedwith a restricted passage means permitting at least a limited flow ofcirculating water normally to pass when said actuating means isinactive.

References Cited in the file of this patent UNITED STATES PATENTS

